Backlight & LCD patches

Backlight & LCD patches

[Andrew Zabolotny]

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Hello!

Here's the patch I've failed to push into mainstream half of year ago,
but with one major modification that avoids the use of the
class_device_find() function that was disliked so much.

The patch must be applied after the fbdev cleanup patch series, notably
after this patch:

http://sourceforge.net/mailarchive/forum.php?thread_id=6206427&forum_id=2357

since it uses the FB_BLANK notification event.

The patch will allow further developement of drivers that allow
controlling backlight and LCD flat panels on hardware that supports it
(in particular, on PDAs).

-- 
Greetings,
   Andrew

[-- Attachment #2: bl-lcd.diff --]
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Signed-off-by: Andrew Zabolotny <zap@homelink.ru>

--- linux-2.6.10/include/linux/lcd.h	1970-01-01 03:00:00.000000000 +0300
+++ linux/include/linux/lcd.h	2005-01-02 01:57:03.000000000 +0300
@@ -0,0 +1,56 @@
+/*
+ * LCD Lowlevel Control Abstraction
+ * 
+ * Copyright (C) 2003,2004 Hewlett-Packard Company
+ * 
+ */
+
+#ifndef _LINUX_LCD_H
+#define _LINUX_LCD_H
+
+#include <linux/device.h>
+#include <linux/notifier.h>
+
+struct lcd_device;
+struct fb_info;
+
+/* This structure defines all the properties of a LCD flat panel. */
+struct lcd_properties {
+	/* Owner module */
+	struct module *owner;
+	/* Get the LCD panel power status (0: full on, 1..3: controller
+	   power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
+	int (*get_power) (struct lcd_device *);
+	/* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
+	int (*set_power) (struct lcd_device *, int power);
+	/* The maximum value for contrast (read-only) */
+	int max_contrast;
+	/* Get the current contrast setting (0-max_contrast) */
+	int (*get_contrast) (struct lcd_device *);
+	/* Set LCD panel contrast */
+        int (*set_contrast) (struct lcd_device *, int contrast);
+	/* Check if given framebuffer device is the one LCD is bound to;
+	   return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */
+	int (*check_fb) (struct fb_info *);
+};
+
+struct lcd_device {
+	/* This protects the 'props' field. If 'props' is NULL, the driver that
+	   registered this device has been unloaded, and if class_get_devdata()
+	   points to something in the body of that driver, it is also invalid. */
+	struct semaphore sem;
+	/* If this is NULL, the backing module is unloaded */
+	struct lcd_properties *props;
+	/* The framebuffer notifier block */
+	struct notifier_block fb_notif;
+	/* The class device structure */
+	struct class_device class_dev;
+};
+
+extern struct lcd_device *lcd_device_register(const char *name,
+	void *devdata, struct lcd_properties *lp);
+extern void lcd_device_unregister(struct lcd_device *ld);
+
+#define to_lcd_device(obj) container_of(obj, struct lcd_device, class_dev)
+
+#endif
--- linux-2.6.10/include/linux/backlight.h	1970-01-01 03:00:00.000000000 +0300
+++ linux/include/linux/backlight.h	2005-01-02 01:57:19.000000000 +0300
@@ -0,0 +1,57 @@
+/*
+ * Backlight Lowlevel Control Abstraction
+ * 
+ * Copyright (C) 2003,2004 Hewlett-Packard Company
+ * 
+ */
+
+#ifndef _LINUX_BACKLIGHT_H
+#define _LINUX_BACKLIGHT_H
+
+#include <linux/device.h>
+#include <linux/notifier.h>
+
+struct backlight_device;
+struct fb_info;
+
+/* This structure defines all the properties of a backlight
+   (usually attached to a LCD). */
+struct backlight_properties {
+	/* Owner module */
+	struct module *owner;
+	/* Get the backlight power status (0: full on, 1..3: power saving
+	   modes; 4: full off), see FB_BLANK_XXX */
+	int (*get_power) (struct backlight_device *);
+	/* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
+	int (*set_power) (struct backlight_device *, int power);
+	/* Maximal value for brightness (read-only) */
+	int max_brightness;
+	/* Get current backlight brightness */
+	int (*get_brightness) (struct backlight_device *);
+	/* Set backlight brightness (0..max_brightness) */
+	int (*set_brightness) (struct backlight_device *, int brightness);
+	/* Check if given framebuffer device is the one bound to this backlight;
+	   return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
+	int (*check_fb) (struct fb_info *);
+};
+
+struct backlight_device {
+	/* This protects the 'props' field. If 'props' is NULL, the driver that
+	   registered this device has been unloaded, and if class_get_devdata()
+	   points to something in the body of that driver, it is also invalid. */
+	struct semaphore sem;
+	/* If this is NULL, the backing module is unloaded */
+	struct backlight_properties *props;
+	/* The framebuffer notifier block */
+	struct notifier_block fb_notif;
+	/* The class device structure */
+	struct class_device class_dev;
+};
+
+extern struct backlight_device *backlight_device_register(const char *name,
+	void *devdata, struct backlight_properties *bp);
+extern void backlight_device_unregister(struct backlight_device *bd);
+
+#define to_backlight_device(obj) container_of(obj, struct backlight_device, class_dev)
+
+#endif
--- linux-2.6.10/drivers/video/backlight/lcd.c	1970-01-01 03:00:00.000000000 +0300
+++ linux/drivers/video/backlight/lcd.c	2004-12-02 21:35:56.000000000 +0300
@@ -0,0 +1,263 @@
+/*
+ * LCD Lowlevel Control Abstraction
+ *
+ * Copyright (C) 2003,2004 Hewlett-Packard Company
+ *
+ */
+
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/lcd.h>
+#include <linux/notifier.h>
+#include <linux/ctype.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <asm/bug.h>
+
+static ssize_t lcd_show_power(struct class_device *cdev, char *buf)
+{
+	int rc;
+	struct lcd_device *ld = to_lcd_device(cdev);
+
+	down (&ld->sem);
+	if (likely (ld->props && ld->props->get_power))
+		rc = sprintf (buf, "%d\n", ld->props->get_power (ld));
+	else
+		rc = -ENXIO;
+	up (&ld->sem);
+
+	return rc;
+}
+
+static ssize_t lcd_store_power(struct class_device *cdev, const char *buf, size_t count)
+{
+	int rc, power;
+	char *endp;
+	struct lcd_device *ld = to_lcd_device(cdev);
+
+	power = simple_strtoul(buf, &endp, 0);
+	if (*endp && !isspace (*endp))
+		return -EINVAL;
+
+	down (&ld->sem);
+	if (likely (ld->props && ld->props->set_power)) {
+		pr_debug("lcd: set power to %d\n", power);
+		ld->props->set_power(ld, power);
+		rc = count;
+	} else
+		rc = -ENXIO;
+	up (&ld->sem);
+
+	return rc;
+}
+
+static ssize_t lcd_show_contrast(struct class_device *cdev, char *buf)
+{
+	int rc;
+	struct lcd_device *ld = to_lcd_device(cdev);
+
+	down (&ld->sem);
+	if (likely (ld->props && ld->props->get_contrast))
+		rc = sprintf (buf, "%d\n", ld->props->get_contrast(ld));
+	else
+		rc = -ENXIO;
+	up (&ld->sem);
+
+	return rc;
+}
+
+static ssize_t lcd_store_contrast(struct class_device *cdev, const char *buf, size_t count)
+{
+	int rc, contrast;
+	char *endp;
+	struct lcd_device *ld = to_lcd_device(cdev);
+
+	contrast = simple_strtoul(buf, &endp, 0);
+	if (*endp && !isspace (*endp))
+		return -EINVAL;
+
+	down (&ld->sem);
+	if (likely (ld->props && ld->props->set_contrast)) {
+		pr_debug("lcd: set contrast to %d\n", contrast);
+		ld->props->set_contrast(ld, contrast);
+		rc = count;
+	} else
+		rc = -ENXIO;
+	up (&ld->sem);
+
+	return rc;
+}
+
+static ssize_t lcd_show_max_contrast(struct class_device *cdev, char *buf)
+{
+	int rc;
+	struct lcd_device *ld = to_lcd_device(cdev);
+
+	down (&ld->sem);
+	if (likely (ld->props))
+		rc = sprintf (buf, "%d\n", ld->props->max_contrast);
+	else
+		rc = -ENXIO;
+	up (&ld->sem);
+
+	return rc;
+}
+
+static void lcd_class_release(struct class_device *dev)
+{
+	struct lcd_device *ld = to_lcd_device (dev);
+	kfree (ld);
+}
+
+struct class lcd_class = {
+	.name = "lcd",
+	.release = lcd_class_release,
+};
+
+#define DECLARE_ATTR(_name,_mode,_show,_store)			\
+	{							 	\
+	.attr	= { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE },	\
+	.show	= _show,					\
+	.store	= _store,					\
+	}
+
+static struct class_device_attribute lcd_class_device_attributes[] = {
+	DECLARE_ATTR (power, 0644, lcd_show_power, lcd_store_power),
+	DECLARE_ATTR (contrast, 0644, lcd_show_contrast, lcd_store_contrast),
+	DECLARE_ATTR (max_contrast, 0444, lcd_show_max_contrast, NULL),
+};
+
+/* This callback gets called when something important happens inside a
+ * framebuffer driver. We're looking if that important event is blanking,
+ * and if it is, we're switching lcd power as well ...
+ */
+static int fb_notifier_callback (struct notifier_block *self,
+				 unsigned long event, void *data)
+{
+	struct lcd_device *ld;
+	struct fb_event *evdata = (struct fb_event *)data;
+
+	/* If we aren't interested in this event, skip it immediately ... */
+	if (event != FB_EVENT_BLANK)
+		return 0;
+
+	ld = container_of (self, struct lcd_device, fb_notif);
+	down (&ld->sem);
+	if (ld->props)
+		if (!ld->props->check_fb || ld->props->check_fb (evdata->info))
+			ld->props->set_power (ld, *(int *)evdata->data);
+	up (&ld->sem);
+	return 0;
+}
+
+/**
+ * lcd_device_register - register a new object of lcd_device class.
+ * @name: the name of the new object (must be the same as the name of the
+ *   respective framebuffer device).
+ * @devdata: an optional pointer to be stored in the class_device. The
+ *   methods may retrieve it by using class_get_devdata (ld->class_dev).
+ * @lp: the lcd properties structure.
+ *
+ * Creates and registers a new lcd class_device. Returns either an ERR_PTR()
+ * or a pointer to the newly allocated device.
+ */
+struct lcd_device *lcd_device_register (const char *name, void *devdata,
+	struct lcd_properties *lp)
+{
+	int i, rc;
+	struct lcd_device *new_ld;
+
+	pr_debug("lcd_device_register: name=%s\n", name);
+
+	new_ld = kmalloc (sizeof (struct lcd_device), GFP_KERNEL);
+	if (unlikely (!new_ld))
+		return ERR_PTR (ENOMEM);
+
+	init_MUTEX (&new_ld->sem);
+	new_ld->props = lp;
+	memset (&new_ld->class_dev, 0, sizeof (new_ld->class_dev));
+	new_ld->class_dev.class = &lcd_class;
+	strlcpy (new_ld->class_dev.class_id, name, KOBJ_NAME_LEN);
+	class_set_devdata (&new_ld->class_dev, devdata);
+
+	rc = class_device_register (&new_ld->class_dev);
+	if (unlikely (rc)) {
+error:		kfree (new_ld);
+		return ERR_PTR (rc);
+	}
+
+	memset (&new_ld->fb_notif, 0, sizeof (new_ld->fb_notif));
+	new_ld->fb_notif.notifier_call = fb_notifier_callback;
+
+	rc = fb_register_client (&new_ld->fb_notif);
+	if (unlikely (rc))
+		goto error;
+
+	for (i = 0; i < ARRAY_SIZE(lcd_class_device_attributes); i++) {
+		rc = class_device_create_file(&new_ld->class_dev,
+					      &lcd_class_device_attributes[i]);
+		if (unlikely (rc)) {
+			while (--i >= 0)
+				class_device_remove_file(&new_ld->class_dev,
+							 &lcd_class_device_attributes[i]);
+			class_device_unregister(&new_ld->class_dev);
+			/* No need to kfree(new_ld) since release() method was called */
+			return ERR_PTR (rc);
+		}
+	}
+
+	return new_ld;
+}
+EXPORT_SYMBOL(lcd_device_register);
+
+/**
+ * lcd_device_unregister - unregisters a object of lcd_device class.
+ * @ld: the lcd device object to be unregistered and freed.
+ *
+ * Unregisters a previously registered via lcd_device_register object.
+ */
+void lcd_device_unregister(struct lcd_device *ld)
+{
+	int i;
+
+	if (!ld)
+		return;
+
+	pr_debug("lcd_device_unregister: name=%s\n", ld->class_dev.class_id);
+
+	for (i = 0; i < ARRAY_SIZE (lcd_class_device_attributes); i++)
+		class_device_remove_file (&ld->class_dev,
+					  &lcd_class_device_attributes[i]);
+
+	down (&ld->sem);
+	ld->props = NULL;
+	up (&ld->sem);
+
+	fb_unregister_client (&ld->fb_notif);
+
+	class_device_unregister(&ld->class_dev);
+}
+EXPORT_SYMBOL(lcd_device_unregister);
+
+static void __exit lcd_class_exit(void)
+{
+	class_unregister(&lcd_class);
+}
+
+static int __init lcd_class_init(void)
+{
+	return class_register(&lcd_class);
+}
+
+/*
+ * if this is compiled into the kernel, we need to ensure that the
+ * class is registered before users of the class try to register lcd's
+ */
+postcore_initcall(lcd_class_init);
+module_exit(lcd_class_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
+MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");
--- linux-2.6.10/drivers/video/backlight/backlight.c	1970-01-01 03:00:00.000000000 +0300
+++ linux/drivers/video/backlight/backlight.c	2004-12-31 22:19:51.000000000 +0300
@@ -0,0 +1,264 @@
+/*
+ * Backlight Lowlevel Control Abstraction
+ *
+ * Copyright (C) 2003,2004 Hewlett-Packard Company
+ *
+ */
+
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/backlight.h>
+#include <linux/notifier.h>
+#include <linux/ctype.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <asm/bug.h>
+
+static ssize_t backlight_show_power (struct class_device *cdev, char *buf)
+{
+	int rc;
+	struct backlight_device *bd = to_backlight_device (cdev);
+
+	down (&bd->sem);
+	if (likely (bd->props && bd->props->get_power))
+		rc = sprintf (buf, "%d\n", bd->props->get_power (bd));
+	else
+		rc = -ENXIO;
+	up (&bd->sem);
+
+	return rc;
+}
+
+static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count)
+{
+	int rc, power;
+	char *endp;
+	struct backlight_device *bd = to_backlight_device (cdev);
+
+	power = simple_strtoul (buf, &endp, 0);
+	if (*endp && !isspace (*endp))
+		return -EINVAL;
+
+	down (&bd->sem);
+	if (likely (bd->props && bd->props->set_power)) {
+		pr_debug("backlight: set power to %d\n", power);
+		bd->props->set_power(bd, power);
+		rc = count;
+	} else
+		rc = -ENXIO;
+	up (&bd->sem);
+
+	return rc;
+}
+
+static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
+{
+	int rc;
+	struct backlight_device *bd = to_backlight_device (cdev);
+
+	down (&bd->sem);
+	if (likely (bd->props && bd->props->get_brightness))
+		rc = sprintf (buf, "%d\n", bd->props->get_brightness (bd));
+	else
+		rc = -ENXIO;
+	up (&bd->sem);
+
+	return rc;
+}
+
+static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count)
+{
+	int rc, brightness;
+	char *endp;
+	struct backlight_device *bd = to_backlight_device (cdev);
+
+	brightness = simple_strtoul (buf, &endp, 0);
+	if (*endp && !isspace (*endp))
+		return -EINVAL;
+
+	down (&bd->sem);
+	if (likely (bd->props && bd->props->set_brightness)) {
+		pr_debug("backlight: set brightness to %d\n", brightness);
+		bd->props->set_brightness(bd, brightness);
+		rc = count;
+	} else
+		rc = -ENXIO;
+	up (&bd->sem);
+
+	return rc;
+}
+
+static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf)
+{
+	int rc;
+	struct backlight_device *bd = to_backlight_device (cdev);
+
+	down (&bd->sem);
+	if (likely (bd->props))
+		rc = sprintf(buf, "%d\n", bd->props->max_brightness);
+	else
+		rc = -ENXIO;
+	up (&bd->sem);
+
+	return rc;
+}
+
+static void backlight_class_release(struct class_device *dev)
+{
+	struct backlight_device *bd = to_backlight_device (dev);
+	kfree (bd);
+}
+
+struct class backlight_class = {
+	.name = "backlight",
+	.release = backlight_class_release,
+};
+
+#define DECLARE_ATTR(_name,_mode,_show,_store)			\
+	{							 	\
+	.attr	= { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE },	\
+	.show	= _show,					\
+	.store	= _store,					\
+	}
+
+static struct class_device_attribute bl_class_device_attributes[] = {
+	DECLARE_ATTR (power, 0644, backlight_show_power, backlight_store_power),
+	DECLARE_ATTR (brightness, 0644, backlight_show_brightness, backlight_store_brightness),
+	DECLARE_ATTR (max_brightness, 0444, backlight_show_max_brightness, NULL),
+};
+
+/* This callback gets called when something important happens inside a
+ * framebuffer driver. We're looking if that important event is blanking,
+ * and if it is, we're switching backlight power as well ...
+ */
+static int fb_notifier_callback (struct notifier_block *self,
+				 unsigned long event, void *data)
+{
+	struct backlight_device *bd;
+	struct fb_event *evdata = (struct fb_event *)data;
+
+	/* If we aren't interested in this event, skip it immediately ... */
+	if (event != FB_EVENT_BLANK)
+		return 0;
+
+	bd = container_of (self, struct backlight_device, fb_notif);
+	down (&bd->sem);
+	if (bd->props)
+		if (!bd->props->check_fb || bd->props->check_fb (evdata->info))
+			bd->props->set_power (bd, *(int *)evdata->data);
+	up (&bd->sem);
+	return 0;
+}
+
+/**
+ * backlight_device_register - create and register a new object of
+ *   backlight_device class.
+ * @name: the name of the new object (must be the same as the name of the
+ *   respective framebuffer device).
+ * @devdata: an optional pointer to be stored in the class_device. The
+ *   methods may retrieve it by using class_get_devdata (&bd->class_dev).
+ * @bp: the backlight properties structure.
+ *
+ * Creates and registers new backlight class_device. Returns either an
+ * ERR_PTR() or a pointer to the newly allocated device.
+ */
+struct backlight_device *backlight_device_register(const char *name,
+	void *devdata, struct backlight_properties *bp)
+{
+	int i, rc;
+	struct backlight_device *new_bd;
+
+	pr_debug("backlight_device_alloc: name=%s\n", name);
+
+	new_bd = kmalloc (sizeof (struct backlight_device), GFP_KERNEL);
+	if (unlikely (!new_bd))
+		return ERR_PTR (ENOMEM);
+
+	init_MUTEX (&new_bd->sem);
+	new_bd->props = bp;
+	memset (&new_bd->class_dev, 0, sizeof (new_bd->class_dev));
+	new_bd->class_dev.class = &backlight_class;
+	strlcpy (new_bd->class_dev.class_id, name, KOBJ_NAME_LEN);
+	class_set_devdata (&new_bd->class_dev, devdata);
+
+	rc = class_device_register (&new_bd->class_dev);
+	if (unlikely (rc)) {
+error:		kfree (new_bd);
+		return ERR_PTR (rc);
+	}
+
+	memset (&new_bd->fb_notif, 0, sizeof (new_bd->fb_notif));
+	new_bd->fb_notif.notifier_call = fb_notifier_callback;
+
+	rc = fb_register_client (&new_bd->fb_notif);
+	if (unlikely (rc))
+		goto error;
+
+	for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) {
+		rc = class_device_create_file(&new_bd->class_dev,
+					      &bl_class_device_attributes[i]);
+		if (unlikely (rc)) {
+			while (--i >= 0)
+				class_device_remove_file(&new_bd->class_dev,
+							 &bl_class_device_attributes[i]);
+			class_device_unregister(&new_bd->class_dev);
+			/* No need to kfree(new_bd) since release() method was called */
+			return ERR_PTR (rc);
+		}
+	}
+
+	return new_bd;
+}
+EXPORT_SYMBOL(backlight_device_register);
+
+/**
+ * backlight_device_unregister - unregisters a backlight device object.
+ * @bd: the backlight device object to be unregistered and freed.
+ *
+ * Unregisters a previously registered via backlight_device_register object.
+ */
+void backlight_device_unregister(struct backlight_device *bd)
+{
+	int i;
+
+	if (!bd)
+		return;
+
+	pr_debug("backlight_device_unregister: name=%s\n", bd->class_dev.class_id);
+
+	for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++)
+		class_device_remove_file (&bd->class_dev,
+					  &bl_class_device_attributes[i]);
+
+	down (&bd->sem);
+	bd->props = NULL;
+	up (&bd->sem);
+
+	fb_unregister_client (&bd->fb_notif);
+
+	class_device_unregister(&bd->class_dev);
+}
+EXPORT_SYMBOL(backlight_device_unregister);
+
+static void __exit backlight_class_exit(void)
+{
+	class_unregister(&backlight_class);
+}
+
+static int __init backlight_class_init(void)
+{
+	return class_register(&backlight_class);
+}
+
+/*
+ * if this is compiled into the kernel, we need to ensure that the
+ * class is registered before users of the class try to register lcd's
+ */
+postcore_initcall(backlight_class_init);
+module_exit(backlight_class_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
+MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");
--- linux-2.6.10/drivers/video/backlight/Kconfig	1970-01-01 03:00:00.000000000 +0300
+++ linux/drivers/video/backlight/Kconfig	2005-01-02 21:58:09.000000000 +0300
@@ -0,0 +1,41 @@
+#
+# Backlight & LCD drivers configuration
+#
+
+menuconfig BACKLIGHT_LCD_SUPPORT
+	bool "Backlight & LCD device support"
+	help
+	  Enable this to be able to choose the drivers for controlling the
+	  backlight and the LCD panel on some platforms, for example on PDAs.
+
+config BACKLIGHT_CLASS_DEVICE
+        tristate "Lowlevel Backlight controls"
+	depends on BACKLIGHT_LCD_SUPPORT
+	help
+	  This framework adds support for low-level control of the LCD
+          backlight. This includes support for brightness and power.
+
+	  To have support for your specific LCD panel you will have to
+	  select the proper drivers which depend on this option.
+
+config BACKLIGHT_DEVICE
+	bool
+	depends on BACKLIGHT_CLASS_DEVICE
+	default y
+
+config LCD_CLASS_DEVICE
+        tristate "Lowlevel LCD controls"
+	depends on BACKLIGHT_LCD_SUPPORT
+	help
+	  This framework adds support for low-level control of LCD.
+	  Some framebuffer devices connect to platform-specific LCD modules
+	  in order to have a platform-specific way to control the flat panel
+	  (contrast and applying power to the LCD (not to the backlight!)).
+
+	  To have support for your specific LCD panel you will have to
+	  select the proper drivers which depend on this option.
+
+config LCD_DEVICE
+	bool
+	depends on LCD_CLASS_DEVICE
+	default y
--- linux-2.6.10/drivers/video/backlight/Makefile	1970-01-01 03:00:00.000000000 +0300
+++ linux/drivers/video/backlight/Makefile	2005-01-02 21:16:16.000000000 +0300
@@ -0,0 +1,4 @@
+# Backlight & LCD drivers
+
+obj-$(CONFIG_LCD_CLASS_DEVICE)     += lcd.o
+obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += backlight.o
--- linux-2.6.10/drivers/video/Kconfig	2004-12-04 11:29:31.000000000 +0300
+++ linux/drivers/video/Kconfig	2005-01-02 22:01:42.000000000 +0300
@@ -1094,5 +1094,9 @@
 	source "drivers/video/logo/Kconfig"
 endif
 
+if SYSFS
+	source "drivers/video/backlight/Kconfig"
+endif
+
 endmenu
 
--- linux-2.6.10/drivers/video/Makefile	2004-12-04 11:29:31.000000000 +0300
+++ linux/drivers/video/Makefile	2005-01-02 22:00:48.000000000 +0300
@@ -6,6 +6,7 @@
 
 obj-$(CONFIG_VT)		  += console/
 obj-$(CONFIG_LOGO)		  += logo/
+obj-$(CONFIG_SYSFS)		  += backlight/
 
 obj-$(CONFIG_FB)                  += fbmem.o fbmon.o fbcmap.o fbsysfs.o modedb.o softcursor.o
 # Only include macmodes.o if we have FB support and are PPC